The field of the present invention is bracing hardware for use in building structures for utility piping.
Building codes, as well as competent construction practice, require the securing of fluid lines and other utilities to the structure of the building to brace such lines against damaging movement resulting from seismic disturbances. Sway braces have been designed for securing numerous types of fluid supply piping. An example of such secured piping is fire control water sprinkler distribution pipes. When sprinkler systems are used in buildings, it is required that the water distribution pipes be adequately braced, so that, in the event of an earthquake, the pipes will not unduly sway relative to adjacent portions of the building and separate or produce excessive leakage at the pipe joints.
Various types of sway brace structures have been developed for the foregoing purpose. Examples of such brace designs are to be found in U.S. Pat. Nos. 3,570,794; 4,697,770; and 6,508,441. Further, a number of devices may be employed for mounting such bracing to a structure. Examples are found in U.S. Pat. Nos. 5,004,193; 5,007,603; 5,145,132; 6,334,285; 6,464,422; and 6,629,678. The disclosures of the aforementioned nine patents are incorporated herein by reference.
Pipe used for utility purposes in construction, such as for fire sprinkler systems, comes in certain sizes and materials. These specified pipe sizes have nominal outside diameters which vary within specific mill tolerances. Such nominal sizes and the associated mill tolerances can differ based on pipe material such as steel, cooper and plastic and on pipe nominal diameter. Hardware applied to such utility pipe of these various specified sizes is frequently designed specifically for a specified size and identified as such. The design of such hardware contemplates the nominal dimensions and, where necessary, the tolerances thereof. Thus, there is a specific relationship and fit achieved by such hardware which is defined by the nominal dimensions within tolerance limits of any given specified utility pipe size for which the hardware is made.
FIG. 1 illustrates a prior art pipe clamp. The clamp is illustrated in its employed state with two bars 10 each defining a first straight section 12, an arcuate section 14 and a second straight section 16. Fasteners 18 hold the two bars 10 together. However, the profile of the arcuate section 14 is designed to position each bar 10 about a pipe such that the straight sections 12 and 16 are not brought together when tightened about a pipe. Wide variations in clamping force can be experienced depending on the amount of tightening applied to the fasteners.